Association between in utero zidovudine exposure and nondefect adverse birth outcomes: analysis of prospectively collected data from the Antiretroviral Pregnancy Registry

ObjectiveTo examine the association between nondefect adverse birth outcomes and in utero exposure to zidovudine (ZDV)-containing regimens versus non-ZDV antiretroviral (ARV) regimens. DesignAnalysis of prospectively-collected data. SettingGlobal. PopulationHIV-infected pregnant women prenatally exposed to antiretrovirals. MethodsEstimation of prevalence of and risk for nondefect adverse birth outcomes among HIV-infected women. Main outcome measuresPrevalence of and risk for nondefect adverse birth outcomes. ResultsAmong 12780 singleton birth outcomes with in utero ZDV exposure, 96.1% were live births; 3.9% were spontaneous abortions, induced abortions or stillbirths. Among live births, 16.4% were low birthweight (LBW); 12.3% were premature. Among 1904 outcomes with in utero exposure to non-ZDV ARV regimens, 85.8% were live births; 14.2% were spontaneous abortions, induced abortions or stillbirths. Among live births, 14.1% were LBW; 12.4% were premature. Relative risk comparing exposure to ZDV-containing ARV regimens to non-ZDV ARV regimens for spontaneous abortions was 0.18 (95% confidence interval [95% CI] 0.14-0.22); induced abortions 0.28 (95% CI 0.22-0.36); stillbirths 0.76 (95% CI 0.51-1.12); premature births 1.00 (95% CI 0.87-1.15) and LBW 1.17 (95% CI 1.02-1.33). ConclusionPrevalence of nondefect adverse birth outcomes is lower among outcomes with in utero ZDV exposure versus in utero non-ZDV ARV exposure. The risks for spontaneous and induced abortions were no different for ZDV-containing regimens versus non-ZDV ARV regimens. For premature births and stillbirths, there was no significant difference in risk between the two regimens. The risk of LBW was statistically significantly higher among ZDV-containing regimens versus non-ZDV ARV regimens. Tweetable abstractZDV-containing regimens do not increase the risk for nondefect adverse birth outcomes. Tweetable abstract ZDV-containing regimens do not increase the risk for nondefect adverse birth outcomes.